1. Field of the Invention
The present invention is in the field of medical treatment of arteriosclerosis and related vascular diseases and, more specifically, discloses the use of nanoparticles for the treatment of vascular disease.
2. Description of Related Art
In spite of some improvements in the American diet over the last generation and an increasing popular understanding in the importance of physical activity, heart and vascular disease continue to be major causes of mortality and morbidity. It is common knowledge that “poor” life style including poor diet and lack of adequate physical activity result in clogging of the arteries with a fatty substance known generally as plaque. It would appear that dietary fats contribute to plaque because consumption of “bad” fats such as animal fats, including cholesterol, and chemically synthesized “trans” fats can be directly correlated with plaque formation.
Common non-invasive treatments include dietary modification and use of cholesterol lowering drugs such as statins. Although such treatments are often successful they are not without side-effects. Further, the exact cause of the problem and the reason for the effectiveness of the treatments is not yet completely clear. On one hand there are a number of cultures where individuals consume high fat diets, often containing significant amount of “bad” fats and yet seem to experience few negative consequences. Many of the so-called Mediterranean diet countries seem to avoid many of the worst consequences of a high fat diet; this is the origin of the “French paradox” where consumption of “killer foods” such as foie gras by the French seem to have little negative impact. Of course, the picture is complicated by other factors experienced by most Mediterraneans. Generally, their diets include relatively high amounts of fresh fruits and vegetables as well as plant fats (e.g. olive oil). Mediterraneans generally walk more than Americans and also consume much more red wine than Americans. Thus, it is difficult to pin point which factors in the Mediterranean diet—or rather life style—contribute to vascular health. Even with cholesterol lowering drugs the picture is a bit murky. Although the drugs are generally successful, they seem to be effective even where the patient already has a very low level of cholesterol. There is considerable evidence that many of the cholesterol lowering drugs are potent anti-inflammatory agents. So is the problem with plaque one of excess cholesterol or of systemic inflammation?
Despite their promise non-invasive treatments for vascular disease cannot help all patients. Many individuals are suffering from serious arterial damage at time of diagnosis. Diets and drugs may prevent plaque formation and may even achieve diminution of existing plaque, but a patient with serious plaque build-up may well suffer a fatal heart attack or embolism before drug treatment even has a chance to work. Therefore, invasive procedures are necessary for individuals with significant plaque deposits. The initial treatment for plaque clogged coronary arteries was an auto-graft using the patient's own saphenous veins or other veins to replace the clogged arteries—known as “bypass” surgery. Unfortunately, bypass surgery is incredibly invasive. Often the patient will not even have harvestable veins suitable for a bypass. Balloon angioplasty followed by the placement of a vascular stent has been developed as a less invasive treatment for arterial blockage. However, angioplasty does not remove the plaque and even with a stent present there can be development of a new blockage. Indeed, the damage to the vascular wall caused by the angioplasty and presence of the stent may even stimulate abnormal cell growth which results in vascular stenosis. Clearly, what is needed is additional non-invasive treatment modalities that can actually destroy the plaque and subsequently promote regeneration of the damaged vascular region.